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Fair Value of Financial Investments and Liabilities - Additional Information (Detail) (USD $) In Billions, unless otherwise specified | Mar. 31, 2013 | Dec. 31, 2012
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Fair Value Disclosures [Abstract] |  |
Estimated market value of long-term and short-term debt | $ 4.0 | $ 4.0
Aggregate carrying value of long-term and short-term debt | $ 3.6 | $ 3.6

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- Definition Aggregate carrying value of long term and short term debt. + References No definition available. + Details
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Namespace Prefix: | mas_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- Definition Estimated market value of long term and short term debt. + References No definition available. + Details
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Namespace Prefix: | mas_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration